1. Field of Invention
This invention relates to a thermal enhance multi-chips module (MCM) package. More particularly, the present invention is related to a thermal enhance MCM package having a cap-like heat spreader and a manufacturing method thereof.
2. Related Art
Recently, integrated circuit (chip) packaging technology is becoming a limiting factor for the development in packaged integrated circuits of higher performance. Semiconductor package designers are struggling to keep pace with the increase in pin count, size limitations, low profile, and other evolving requirements for packaging and mounting integrated circuits.
Due to the assembly package in miniature and the integrated circuits operation in high frequency, MCM (multi-chips module) package is commonly used in the assembly package and electronic devices. Usually, the MCM package mainly comprises at least two chips encapsulated therein, for example a processor unit, a memory unit and related logic units, so as to upgrade the electrical performance of said assembly package. In addition, the electrical paths between the chips in said MCM package are short so as to reduce the signal delay and save the reading and writing time.
Generally speaking, as shown in FIG. 1, it illustrates the top view of a conventional assembly package in a side-by-side type. Two assembly packages 11 and 12 are disposed on a carrier 13, for example an organic substrate, in parallel with each other, and electrically connected to external electronic devices through electrically conductive devices 14, for example, solder balls. Moreover, the multi-chips module assembly package (MCM assembly package) may be an assembly package in a stacked type as shown in FIG. 2 or an assembly package with an intermediate substrate 20 therein as shown in FIG. 3 and FIG. 4.
As shown in FIG. 2, a first assembly package 21 comprises a first substrate 211 and a first chip 212, wherein the first chip 212 is flip-chip bonded to and electrically connected to the first substrate 211; and a second assembly package 22 comprises a second substrate 221 and a second chip 222 which is flip-chip bonded to and electrically connected to the second substrate 221. Therein, the first package 21 and the second package 22 can also be wire-bond packages. In addition, the first package 21 further comprises a first electrically conductive device 213, for example a solder ball, mounted on the lower surface of the first substrate 221 to electrically connect to the second package 22 through the second substrate 221. Similarly, the second package 22 further comprises a second conductive device 223 formed on the lower surface of the second substrate 221 to transmit the electrical signals from the first package 21 and the second package 22 to an external device. In general, the first assembly package 21 connects to the second assembly package 22, and then secures to the second assembly package after reflowing the solder balls 213. However, before performing the reflowing process, the solder balls 213 may not align with the pads on the lower surface of the first substrate 211 and the pads on the upper surface of the second substrate 221. In such a manner, the first assembly package 21 will not electrically connect to the second assembly package well.
Next, referring to FIG. 3 and FIG. 4, which illustrate another stacked-type assembly package. It should be noted that the reference numeral of each element in FIGS. 3 and 4 corresponds to the same reference numeral of each element in FIG. 2. There is an opening 201 formed in an intermediate substrate 20; the second chip 222 of the second assembly package 22 is disposed in the opening 206 and electrically connected to the first package 21. Therein, the first package 21 comprises a first electrically conductive device 213, for example a solder ball, formed on the lower surface of the first substrate 211 to electrically connect to the intermediate substrate 20, and the lower surface of the intermediate substrate 20 has a third electrically conductive device 23 formed thereon to electrically connect to the second assembly package 22. In addition, the second assembly package 22 further comprises a second electrically conductive device 223 formed on the lower surface of the second substrate 221 to transmit the electrical signals from the first package 21 and the second package 22 to an external device through the intermediate substrate 20.
As mentioned above, the second assembly package 22 secures to the intermediate substrate 20 by reflowing the solder balls 23. Similarly, the first assembly package 21 secures to the intermediate substrate 20 by reflowing the solder balls 213. However, before the solder balls 23 and 213 are secured to the first assembly package 21 and the second assembly package 22, the solder balls 23 may not align with the pads on the lower surface of the first substrate 211 and the pads on the upper surface of the intermediate substrate 20 and the solder balls 213 may not align with the pads on the lower surface of the intermediate substrate 20 and the pads on the upper surface of the second substrate 221. In such a manner, the first assembly package 21 will not electrically connect to the intermediate substrate well, and the second assembly package 22 will also not electrically connect to the intermediate substrate well. Besides, the first assembly package 21 is secured to the intermediate substrate 20 after the second assembly package securing to the intermediate by reflowing the solder balls 23, so the assembly cost and assembly time for manufacturing above-mentioned MCM package will be increased.
Therefore, providing another assembly package to solve the mentioned-above disadvantages is the most important task in this invention.